'use strict';

/**
 * agg_sort_external.js
 *
 * Runs an aggregation with a $match that returns half the documents followed
 * by a $sort on a field containing a random float.
 *
 * The data returned by the $match is greater than 100MB, which should force an external sort.
 */
load('jstests/concurrency/fsm_libs/extend_workload.js');         // for extendWorkload
load('jstests/concurrency/fsm_workloads/agg_base.js');           // for $config
load('jstests/concurrency/fsm_workload_helpers/drop_utils.js');  // for dropCollections

var $config = extendWorkload(
    $config,
    function($config, $super) {

        // use enough docs to exceed 100MB, the in-memory limit for $sort and $group
        $config.data.numDocs = 24 * 1000;
        var MB = 1024 * 1024;  // bytes
        // assert that *half* the docs exceed the in-memory limit, because the $match stage will
        // only
        // pass half the docs in the collection on to the $sort stage.
        assertAlways.lte(100 * MB, $config.data.numDocs * $config.data.docSize / 2);

        $config.data.getOutputCollPrefix = function getOutputCollPrefix(collName) {
            return collName + '_out_agg_sort_external_';
        };

        $config.states.query = function query(db, collName) {
            var otherCollName = this.getOutputCollPrefix(collName) + this.tid;
            var cursor =
                db[collName]
                    .aggregate([{$match: {flag: true}}, {$sort: {rand: 1}}, {$out: otherCollName}],
                               {allowDiskUse: true});
            assertAlways.eq(0, cursor.itcount());
            assertWhenOwnColl.eq(db[collName].find().itcount() / 2,
                                 db[otherCollName].find().itcount());
        };

        $config.teardown = function teardown(db, collName, cluster) {
            $super.teardown.apply(this, arguments);

            // drop all collections with this workload's assumed-to-be-unique prefix
            // NOTE: assumes the prefix contains no special regex chars
            dropCollections(db, new RegExp('^' + this.getOutputCollPrefix(collName)));
        };

        return $config;
    });
